NANOSCALE PROBING AND PHOTONIC APPLICATIONS OF FERROELECTRIC DOMAIN WALLS
Open Access
- Author:
- Tian, Lili
- Graduate Program:
- Materials Science and Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 23, 2006
- Committee Members:
- Venkatraman Gopalan, Committee Chair/Co-Chair
Leslie Eric Cross, Committee Member
Qiming Zhang, Committee Member
Zhiwen Liu, Committee Member - Keywords:
- ferroelectrics
SPM
PFM
nanoscale
lithium niobate
lithium tantalate - Abstract:
- Ferroelectrics are a versatile solid-state platform for a new generation of micro- and nanophotonic applications. Conventional integrated optics has often treated the phenomenon of ferroelectric domains and domain walls more as a nuisance rather than an asset. Ironically, domain walls can be immensely valuable in realizing a wide variety of new functionalities such as laser scanning, dynamic focusing, frequency conversion, beam shaping, waveguiding, high-speed modulation, and photonic crystal structures. All of these functions can be realized by shaping ferroelectric domain walls into arbitrary shapes on micro to nanoscale dimensions. Domain walls, however, have a mind of their own when it comes to shaping them. This thesis will focus on the fundamental domain switching characteristics under the uniform electrical fields, and local electromechanical response across the single ferroelectric domain wall in ferroelectric crystals lithium niobate, lithium tantalate and strontium barium niobate. The local electromechanical response across the single was modeled using finite element method to better understand the fundamentals of piezoelectric force microscopy in order to quantitatively interpret the measured material properties. The influence of stoichiometry on domain dynamics on macroscale and on local electromechanical properties on nanoscale was studied. The challenges in shaping ferroelectric domain are discussed and the examples of optical devices such as optical switch and optical beam deflector based on ferroelectric domain walls are presented.